Light redirection devices may be used in conjunction with image display elements, including, but not limited to liquid crystal display (LCD) panels, to redirect light from the image display element in a predetermined direction so as to project an image in a predetermined direction, for example, toward a viewer of the display element. For example, such light redirection devices may be used in aeronautical settings to redirect light, and thus an image generated by a LCD panel, from the LCD panel toward a pilot in the airplane's cockpit.
One conventional light redirection device includes a film comprising a transparent optical composite forming a series of micro-replicated prismatic structures. The film is configured to receive an input image (e.g., light from an LCD panel) and redirect the input image at a predetermined viewing angle. The predetermined viewing angle at which the light redirection film redirects the light is a fixed angle depending on the configuration of the prismatic structures of the film. Such conventional light redirection films therefore do not permit an observer of the image projected by the LCD panel to selectively modulate the angle at which the light (image) is redirected. Rather, the film configuration dictates the fixed angle at which light will be redirected, as opposed to a user being able to adjust that redirection angle, and thus the angle at which an image is projected, as desired.
It may therefore be desirable to provide light redirection devices and methods that permit the angle at which the image is projected to be adjusted by a user, such as an observer desiring to view the image projected. In other words, it may be desirable to provide tunable (e.g., selectively modulatable) light redirection devices and methods. In this way, a viewer, such as a pilot in a cockpit or individual in an automobile, for example, may adjust the angle at which the light from an image display element, such as, a LCD panel, for example, is transmitted so as to obtain an image that is optimally projected toward the location of the viewer. Further, it may be desirable to provide light redirection devices and methods that redirect light in two dimensions.
It also may be desirable to provide light redirection devices and methods that are programmable and/or automated.
It may further be desirable to provide a light redirection device that does not require moving, mechanical parts to achieve redirection of the light. Also, it may be desirable to provide such a light redirection device that substantially resists wear.
Moreover, it may be desirable to provide light redirection methods and devices that are capable of projecting a three-dimensional image.